Below is the percentage of Democrats voting for the Democratic nominee for President, drawing on National Election Studies data from 1952-2004.
This graph should be the starting point for any discussion of a “deeply divided” or “fractured” Democratic Party. The party loyalty of Democrats has been increasing over time and has essentially hovered at 90% since 1992. (And Republicans are similarly loyal to the Republican nominee.)
A central finding of political science research into campaign effects is this: during the general election, presidential campaigns tend to reinforce one’s preexisting partisan leaning. In other words, they tend to unify the party.
The tendency now, as in the NY Times and Washington Post pieces linked above, is to ponder, ominously, “divides” within the Democratic Party and, elsewhere, to quote meaningless exit poll data about how many Clinton voters say they will stay home or vote for McCain. Instead, journalists and commentators should be grappling with the reinforcement effect and party loyalty.
Early data from this election also portends a high degree of party loyalty. See this, from an April Pew poll. Already, large percentages of Democrats (77%) say they will vote for Obama against McCain. (Party loyalty among Democrats in the unlikely Clinton-McCain race is 81% — which, given sampling error, is indistinguishable from 77%.) Republicans are, right now, more unified (85% say they will vote for McCain), but this isn’t surprising, since the Republican race has been decided for much longer.[1]
Thus, it’s not clear why Pew entitles the table “Obama’s Struggle within the Democratic Base.” Obama does just as well as Clinton among Democrats. Moreover, and most importantly, he will likely do better as soon as Clinton drops out and the general election campaign begins its inevitable reinforcement effect.
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Addendum: Below is a picture of what reinforcement looks like. The graph derives from National Anneberg Election Study data. It presents the percent of Democrats who said they would vote for Gore over Bush. The data derive from samples taken daily from December 14, 1999, until November 6, 2000. Early on, about 78% of Democrats said they would vote for Gore. That increased to 87% over the course of the campaign.
[1] Independents, by the way, favor Obama over McCain, 52-41. That difference should be close to statistical significance.